The court fight over filling Minnesota's vacant U.S. Senate seat begins in earnest today when Al Franken asks a three-judge panel to dismiss Norm Coleman's lawsuit challenging a recount that left him trailing Franken by 225 votes.

Franken, a Democrat, argues that Minnesota law and the U.S. Constitution prevent Coleman, a Republican, from waging an exhaustive review of the recount that was certified by the state Canvassing Board and give the U.S. Senate power to fill the seat.

Coleman says state law permits a court challenge to press his claims of widespread voting irregularities, including assertions that absentee ballots from Republican-leaning areas were wrongly rejected and that ballots in DFL areas were counted twice.

Meanwhile, the avalanche of legal filings continued Tuesday.

Franken filed a legal brief supporting his argument that the Minnesota Supreme Court should order Gov. Tim Pawlenty and Secretary of State Mark Ritchie to certify him the winner.

And Attorney General Lori Swanson, representing the secretary of state, opposed a Coleman subpoena that seeks testimony from a state elections official regarding the campaign's claim that discrepancies in recount figures may have cost the Republican 10 to 15 votes.

While Coleman recount lawyer Tony Trimble called the subpoena flap "a minor issue in the scheme of things," it underscores how Coleman is leaving no stone unturned in a search for votes that might close the gap.

In his motion seeking dismissal of Coleman's suit, Franken hopes to convince the three-judge panel that state law conveys limited authority for courts to review congressional elections. A court can verify the math of the recount and other technical decisions of the Canvassing Board, but it cannot explore claims of irregularities or election law violations, Franken's lawyers wrote.

Moreover, they said the U.S. Constitution grants the Senate and the House power to be "the judge of the elections, returns and qualifications of its own members."

The motion also cites a 1950 Minnesota court decision that said "it is clear that our courts have no jurisdiction over the election of representatives to Congress, but that Congress is its own judge. ..."

Some legal observers are skeptical about Franken's chances of prevailing on his motion because they say state law appears to allow a vigorous challenge of the Canvassing Board results and because they believe the panel will take its direction from the Minnesota Supreme Court, which gave Coleman the option of bringing some of those claims to court after the recount.

In addition to contending that 654 absentee ballots may have been improperly rejected and that up to 150 other ballots were double-counted, Coleman has questioned 133 missing ballots in a Minneapolis precinct that he said artificially inflated Franken's lead.

But he also has signaled a willingness to wage a much broader review, checking all 12,000 absentee ballots that were rejected to see if any of them were improperly discarded.

Battle over certification

Franken's motion to dismiss dovetails with his renewed effort Tuesday to be certified the winner.

In a brief filed with the state Supreme Court, the campaign makes arguments similar to those it raises in seeking to dismiss the Coleman court challenge. The brief says state election law requires that Pawlenty and Ritchie certify Franken pending the resolution of any court contest, and that failure to do so also runs afoul of federal law.

"Two state officials have blocked the seating of a United States Senator beyond the deadline in federal constitution and statute," the brief said, calling it "an impermissible encroachment into the affairs of the federal government."

The Coleman campaign and some nonpartisan legal experts say state law prevents the governor and the secretary of state from issuing an election certificate if a lawsuit is filed within seven days of when the Canvassing Board certifies election results; Coleman sued a day after the board action. Pawlenty and Ritchie refused an earlier request to certify Franken.

Coleman spokesman Mark Drake said Tuesday: "It is clear that that is not yet an accurate vote total and that Al Franken is not entitled to a certificate of election."

Coleman camp's subpoena

Regarding the subpoena from the Coleman campaign, Trimble said recount tallies reported by local elections officials varied from those posted on the Secretary of State's website and that the campaign wanted to question Deputy Secretary of State Gary Poser about it.

State Director of Elections Jim Gelbmann said Tuesday that both sides were given spreadsheets of the recounts before the tallies went to the Canvassing Board and had opportunities to challenge the figures. He said he was unaware of any discrepancy.

Swanson said courts can reject a subpoena when it "subjects a public official to an undue and unnecessary burden," but Gelbmann said the office would make Poser available and provide requested documents, and it just needed more time to do so. Trimble later said he was confident the campaign would obtain the information.

Dan Johnson, a Republican state lawmaker in Kentucky known for inflammatory Facebook posts comparing Barack and Michelle Obama to monkeys and who defiantly denied allegations that he sexually assaulted a teenage girl in the basement of his home, killed himself Wednesday night. He was 57.